Apparatus for producing fiber reinforced sponge sheeting



June 27, 1961 F. PEKAREK 2,989,775

APPARATUS FOR PRODUCING FIBER REINFORCED SPONGE SHEETING Filed May 1,1959 IN V EN TOR.- Frank Pkark.

AT TOP? N EY.

United States Patent 2,989,775 APPARATUS FOR PRODUCING FIBER REIN-FORCED SPONGE SHEETING Frank Pekarek, Cleveland, Ohio, assignor toNylonge Corporation, Cleveland, Ohio, a corporation of Ohio Filed May 1,1959, Ser. No. 810,474 11 Claims. (Cl. 18-'4) The present inventionrelates generally to an improved extrusion method and apparatus and itrelates more particnlarly to an improved method and apparatus for theproduction of fiber reinforced sponge cloth.

'lhin sheets of artificial sponge material have been generally employedfor cleaning and polishing purposes. Such sheets, particularly when theyare formed of viscose produced regenerated cellulose are provided withreinforcing fibers to increase the strength and useful life thereof. Thethin sheets have been fabricated by cutting. them from a block of thesponge or they are directly-extruded as a thin sheet or cloth. In theformer case the process is expensive and the end product lacksuniformity, strength and other desired physical properties. In thelatter case although the cost of the end product is relatively low, itpossesses a drawback and disadvantage. While the strength of theextruded sponge cloth is satisfactory in the direction of extrusion, thestrength thereof transverse to the direction of the extrusion is verylow and entirely inadequate and the result is an unacceptable product.The reason for the lack of strength across the direction of extrusion isthat the reinforcing fibers are oriented in the direction of extrusionproviding little reinforcing across the direction of extrusion.

It is therefore a principal object of the present invention to providean improved extrusion method and apparatus. I

Another object of the present invention is to provide an improvedapparatus for the production of fiber reinforced sponge cloth orsheeting.

Still another object of the present invention is to provide an improvedapparatus for the production of fiber reinforced sponge cloth orsheeting characterized by the high uniform strength of the end productsubstantially independent of the direction of stress.

A further object of the present invention is to provide an improvedapparatus for the production of fiber reinforced sponge cloth or sheetwherein a substantially random orientation is imparted to thereinforcing fibers.

Still a further object of the present invention is to provide animproved apparatus of the above nature characterized by its simplicity,ruggedness, low cost and high capacity.

The above and other objects of the present invention will becomeapparent from a reading of the following description taken inconjunction with the accompanying drawing, wherein:

' FIGURE 1 is a top plan view of an improved apparatus embodying thepresent invention, shown partially broken away for convenience ofillustration;

FIGURE 2 is a sectional view taken along line 2-2 in FIGURE 1; and

FIGURE 3 is a sectional view taken along line 3-3 in FIGURE 2.

The present invention is based upon the discovery that when a flowablefi-ber carrying sponge forming mass is deposited on an advancing beltconveyor and continuously spread on the conveyor to the desired depth orthickness by a lip member extending diagonally across the conveyor andmoving along its length with a component in'the direction of advance ofthe conveyor, which component should be approximately equal to the speedof the conveyor, the resulting sponge cloth produced thereby ischaracterized by its high uniform strength which is independent ofdirection. It is believed that the uniformity in strength which isindependent of direction is achieved by reason of the random orientationof the reinforcing fibers in the resulting cloth as contrasted to spongecloth produced with conventional extrusion apparatus. In a sense,therefore, the present invention contemplates the provision of animproved extrusion apparatus of the character described comprising anendless band conveyor having an upper advancing run provided with anupwardly directed face, means for depositing a flowable mass on saidconveyor face, an endless second band extending diagonally across saidconveyor face forward of said mass depositing means and having a bottomedge substantially parallel to and confronting and spaced above saidconveyor face, and means driving said conveyor to have a component inthe direction of advance of said conveyor.

According to a preferred form of the present invention the feed run ofthe conveyor band is upwardly forwardly inclined and travels across anunderlying support plate. An open bottom distributing chamber extendsdiagonally across the face of the conveyor and has a longitudinalforwardly directed opening in the front thereof directly above theconveyor face. An endless second band registers with the chamberforwardly directed opening and extends therewith diagonally across theconveyor face and is slightly rearwardly upwardly inclined relativethereto. The lower edge of the second band is spaced a short distanceabove the conveyor face to define therewith an extrusion opening fromthe dis tributing chamber. The conveyor and second band are so driventhat the run of the band registering with the chamber opening is sodriven that it has a component of movement in the direction of advanceof conveyor, said component being of a speed approximately equal to thespeed of advance of the conveyor belt, that is the speed of conveyorbelt plus or minus less than about 20% thereof. It is believed, that inthe aforesaid arrangement that the second hand not only effects theorientless extrusion of the sponge forming mass, but it also eifects apumping mixing of the mass in the distributing chamber so as to disturband avoid any orientation of the material therein.

Referring now to the drawing which illustrates a preferred embodiment ofthe present invention the reference numeral 10 generally designates theimproved apparatus which comprises a continuous conveyor system 11 and afluid mass depositing and spreading system 12. The conveyor system 11includes a suitably mounted substantially planar support plate 13 ofrectangular configuration and forwardly upwardly inclined an angle ofseveral degrees. The trailing and leading ends of the support plate 13terminate in curved depending lips 14 and 15 respectively. An endlessflexible conveyor band or belt 16. has an upper run 17 extendinglongitudinally across the top face of the support plate 13 and advancingalong a direction from the trailing lip 14 to the leading lip 15. Thetrailing end of the conveyor belt 16 passes over and in engagement witha drum 18 and the portion .of' the upper run 17 thereof forward of theleading lip 15 passes over an idler roll 19, the top face of the supportplate 13 lying along the plane tangent to the drum 18 and roll 19.Following the idler roll 19 the conveyor belt 16 passes through aviscose coagulating zone which may be a tank containing a fluid atelevated temperatures; an infra-red heating zone, an electric currentapplying arrangement or the like and thence about a leading drum andalong a return run to the trailing drum 18. The trailing drum 18 ispositively driven at a variable predetermined speed by means of anelectric motor 20 coupled thereto through a variable speed reductionunit 21. It should be noted that the belt 16 is suitably supported alongits length and that the leading drum may be an idler or may bepositively driven in the manner of the trailing drum in which lattercase the drum 13 may idle. The conveyor belt 16 is of any desired width,for example approximately four feet, and is narrower than and extendsmedially across the support plate 13 to leave uncovered laterally spacedlongitudinally extending borders 22. Further, the belt 16 has acontoured, preferably checkered upper or outer conveying face 23 and isformed of any suitable reinforced flexible material such as a natural orsynthetic rubber which is resistant to the ambient environment.

The mass depositing and spreading system 12 includes a suitablysupported elongated hopper or distributing chamber 26 which extendsdiagonally across the upper face of the conveyor upper run 17 in thearea supported by the plate 13 and between diagonally opposite cornersof the plate 13. The chamber 26 preferably extends at an angle ofbetween 30 and 75 for example between 40" and 60 to the direction ofadvance of the conveyor belt 16 and its ends overlie the plate borders22. The distributing chamber 26 comprises a rear wall including a lowerflat section projecting at an angle to, and upwardly and rearwardly fromthe top face of the belt upper nm 17 and terminating in a flat verticaltop section 28. Projecting forwardly from the rear wall upper and lowersections 27 and 28 are substantially cylindrical end walls 29 and 30whichextend beyond the corresponding edges of the conveyor belt 16. Anupper front vertical wall section 32 extends diagonally between theleading upper edges of the end walls 29 and 30 and parallel to the rearwall section 28. A forwardly directed diagonally extending rectangularchamber opening 33 is delineated by the lower edge of the front wall 32,the front edges of the end walls 29 and 30 and the top face of the beltupper run 17, the opening 33 forming an angle to the belt face and beingupwardly rearwardly inclined. The end wall 29 extends to the supportplate top face, its forward edge being disposed outside the conveyoredge and being provided with an inwardly projecting arm lying in theplane of the opening 33 and extending a short distance above theconveyor belt top face and terminating in a forwardly directed lip 34along the outer edge of the belt upper run 17. A second forwardlydirected lip 36, of the same height as the lip 34 projects from theinner edge of the end wall 30 along the opposite longitudinal edge ofthe conveyor belt 16.

The lower edge of the end wall 30 and the adjacent lower edge of therear wall section 27 extend to the support plate top face. A top wall 37covers the chamber 26 and is provided with an opening 38 at its trailingend. A delivery conduit 39 is located directly above and discharges intothe opening 38, and communicates with a source of sponge forming mass.

An elongated endless flat band 40 is disposed above and extendsdiagonally across the top trailing face of the conveyor belt upper run17 and is supported by and between a pair of longitudinally offset drums41 which are located adjacent opposite edges of the support plate 13.The drums 41 are upwardly rearwardly inclined several degrees to aperpendicular to the surface of the conveyor belt upper run 17. Theendless band 40 includes a trailing advancing run 42 and a leadingparallel return run 43. The belt advance run 42 registers the chamberfront opening 33 and extends beyond the edges of the conveyor belt upperrun 17. The upper edge 44 of the band 40 along its advance run 42 isdisposed below and along the lower edge of the chamber front wall 32 andthe bottom edge 46 of the band 40 along its advance run 42 is parallelto and a short distance above the confronting upper face of the conveyorbelt 16 which distance is determined by the desired thickness of the endproduct and may be of the order of about A; inch to 34 inch. The bandadvance run 42 defines the fiont wall of the chamber 26 and an elongatedslot between the bottom edge 46 of the band advance run 42 and theconfronting face of the conveyor belt 16, which slot extends between thelips 34 and 36 and defines an extrusion opening. By reason of theinclination of the belt 40, the lower edge along the return run thereofis disposed a greater distance above the belt top face than the edge 46.A backing plate 47 extends along the inner face of the band advance run42 and is provided with a longitudinally extending medially locatedpositioning slot which slidably engages a corresponding ridge 49medially peripherally extending along the inner face of the band 40. Theband 40 may be formed of any suitable chemical resistant flexiblematerial.

One or both of the drums 41 are positively driven by the electric motor20 through a variable speed reduction unit 50 which is connected to thedrum shafts in conventional fashion. The band 40 is driven in such asense that it moves along its advance run 42 forwardly along andlaterally across the conveyor belt upper run 17 having a component ofmovement in the direction of advance of the conveyor belt 16.Furthermore it is highly desirable and advantageous to drive the band 40at a speed whose component in the direction of the advance of theconveyor belt 16 is approximately equal to the advancing speed of theconveyor belt 16, that is between about plus and minus twenty percent ofsuch speed. Furthermore, it has been found in practice, that the speedof the band 40 should preferably not exceed 100 inches per minute.

Examples of suitable linear speeds of the band 40 for various angles ofthe advance run 42 to the longitudinal direction of advance of theconveyor belt 16 whose speed is 30 inches per minute are as follows: at45 -42 inches per minute; 50-47 inches per minute; 52 inches per minute;'60 inches per minute; 71 inches per minute; --82 inches per minute; and75-ll5 inches per minute.

In accordance with an example of producing a sponge cloth, employing thepresent improved apparatus, a fiber reinforced viscose sponge formingmass is produced by steeping sheets of cellulose containing between 40and 50 pounds alpha cellulose, forexample, 45 pounds of alpha cellulosein an approximately 18 /2% sodium hydroxide solution for a timesufiicient to convert the cellulose into alkali cellulose. The excesssodium hydroxide solution is then expressed from the resulting alkalicellulose in the conventional manner and the unaged alkali cellulose isadmixed with between 15 and 35 pounds of carbon bisulfide, for example,approximately 27 pounds of carbon bisulfide, and the resulting mixtureis tumbled in a suitable drum until cellulose xanthate is produced inaccordance with the general practice. The resulting cellulose xanthateis dissolved in a weak sodium hydroxide solution in an amount to produceapproximately 600 pounds of viscose having an analysis of between 6% and9% cellulose, for example, 7.6% cellulose, 5% to 7% of total alkalinity,for example, 7% and between 3.3% and 5% total sulfur, for example, 3.5%.

To the 600 pounds of viscose in a green unripened condition is thenadded from 15 to 30 pounds, for example, 20 pounds of thoroughly openedhemp fibers having an average staple length. of approximately inch to 1inch and thorough mixing is effected, preferably by means of a doubledelta blade mixing machine maintaining the mass at a temperature notexceeding 15 C. This initial mixing period is approximately 20 minutes.To the resulting mass is added between 1500 and 2500 pounds, forexample, 2000 pounds sodium sulfate decahydrate crystals having anaverage particle size of about 1 to 2, millimeters. The mixing iscontinued for approximately 10, minutes while maintaining thetemperature at about 15 C. or less. It should be noted that any othersuitable methods may be employed, for producing viscose having thedesired properties. An example of such a method is the so-called onestep method which is set forth in the literature.

asserts 1 -The above viscose sponge forming mass is continuouslyintroduced into the-chamber 26 to maintain the level therein atapproximately the level of the band edge 44. The conveyor belt 16 isdriven at approximately 30 inches per minute and the band 40, whichextends at an angle of about 69 to the longitudinal direction of theconveyor b'elt' is driven at a'linear speed of about 60 inches perminute. The conveyor belt 16 carries a sheet of sponge forming mass ofuniform thicknessfromthe open bottom of the chamber 26, the belt 16entering the chamber 26 directly below the bottom edge of the rear wallsection 27 and leaving-the chamber at the lower edge 46 of the band 40.The depth of the sheet 51 is determined by the-height ofthe band oflower edge 46 above the conveyor belt confronting face and by the speedof the conveyor belt. While carried by the belt 16 the sponge formingmass is transported through a coagulating zone, such as a coagulatingliquid of well known composition at an elevated temperature where theviscose is coagulated, the cellulose regenerated and the pore formingcrystals substantially leached out. The sponge sheet is then separatedfrom the belt 16 and transported through washing, bleaching andplasticizing baths and a series of squeeze rolls to produce the finishedsponge which may be cut to the desired sizes.

The resulting sponge cloth is characterized by its uniformly highstrength along both its longitudinal. and transverse directions. This isin contrast to sponge cloth produced by conventional extrusion where thestrength of the sponge sheet transverse to the extrusion direction isonly a small fraction of its strength parallel to the direction ofextrusion. This highly desirable result is believed to be a consequenceof the random orientation of the fibers in the sponge cloth asdistinguished from the conventionally extruded sponge cloth where thefibers are oriented in a longitudinal direction. This random orientationappears to be accomplished primarily by the extrusion edge 46 advancingin the direction of advance of the extruded sheet 50 so that a minimumof stress or strain is applied to the extruded sheet in the directionalong its surface. Another contributing factor may be the mass mixingand agitating action of the inner surface of the band 40. It has beenobserved that the mass in the chamber 26 is carried by the band 40forwardly and upwardly along the leading portion of the chamber where itmoves toward the trailing portion of the chamber 26 and flows downwardlytoward the bottom opposite end by gravity.

While there has been illustrated and described a preferred embodiment ofthe present invention it is apparent that numerous alterations,omissions and additions may be made Without departing fromthe spiritthereof.

What is claimed is:

1. An improved extrusion apparatus of the character described comprisingan endless first band conveyor having an upwardly directed face along anadvancing run thereof, a distributing chamber extending transverselyalong said conveyor upwardly directed face and having a bottom openingformed therein and confronting said face, an endless second handdefining the front wall of said chamber and having a lower edge disposedabove said conveyor face and means advancing said second hand.

2. An improve extrusion apparatus of the character described comprisingan endless driven longitudinally extending first :band conveyor havingan upwardly directed face along an advancing run thereof, a transverselyextending distributing chamber disposed along said conveyor face andhaving formed therein a bottom opening confronting said conveyor faceand a forwardly directed opening extending transversely along andupwardly from said conveyor face and a second driven endless band havinga longitudinal run registering with and extending along said forwardlydirected opening and having a bottom edge disposed above said conveyorface.

3. An improved extrusion apparatus of the character des'c'rib'e'd'comprising 'an endless driven longitudinallyextendirig firstbandconveyor having an upwardly directed face along an advancing runthereof,'a transversely extending distributing chamber disposed alongsaid conveyor "face and having formed therein a bottom openingconfronting said conveyor face and a forwardly directed openingextending diagonally across and upwardly from said conveyor face, and asecond driven endless band having a longitudinal run registering withand extending diagonally across said conveyor face and along saidforwardly directed opening and having a bottom edge disposed above saidconveyor face.

l 4. Animproved extrusion apparatus in accordance with clairn 3 whereinsaid second band has a component of velocity in the direction of advanceand approximately equal to the speed of said conveyor band.

5. An improved extrusion apparatus of the character described comprisingan endless driven longitudinally extending first band conveyor having anupwardly directed face along an advancing run thereof, a transverselyextending distributing chamber disposed along said conveyor face andhaving formed therein a bottom opening confronting said conveyor faceand a forwardly directed opening extending transversely along andupwardly and rearwardly from said conveyor face and a second drivenendless band having a longitudinal run registering with and extendingalong said forwardly directed opening and having a bottom edge disposedabove said conveyor face, and being upwardly, rearwardly inclined fromsaid bottom edge.

6. An improved extrusion apparatus of the character described comprisingan endless driven longitudinally extending first band conveyor having anupwardly directed forwardly upwardly inclined face along an advancingrun thereof, a transversely extending distributing chamber disposedalong said conveyor face and having formed therein a bottom openingconfronting said conveyor face and a forwardly directed openingextending diagonally across and upwardly and rearwardly from saidconveyor face and a second driven endless band having a longitudinal runregistering with and extending along said forwardly directed opening andhaving a bottom edge disposed above said conveyor face and beingupwardly and rearwardly inclined from said bottom edge.

7. An improved extrusion apparatus of the character described comprisinga base plate having an upper face, an open bottom distributing chamberlocated above and extending across said base plate and having formedtherein a forwardly directed opening, an endless driven first bandconveyor having an upper run extending along said upper face betweensaid distributing chamber and said base plate and advancing forwardly ofsaid opening, said conveyor band being of a width substantially equal tothe Width of said forwardly directed opening and a second driven endlessband having a longitudinal run registering with and extending along saidforwardly directed opening and having a bottom edge disposed above saidconveyor upper run.

8. An apparatus in accordance with claim 7 wherein said second bandalong said longitudinal run is upwardly rearwardly inclined.

9. An apparatus in accordance with claim 7 wherein said chamberforwardly directed opening extends diagonally across said conveyor.

10. An improved extrusion apparatus of the character describedcomprising an endless first band conveyor having an upwardly directedface along an advancing run thereof, a distributing chamber extendingtransversely along said conveyor upwardly directed face and havingformed therein a bottom opening confronting said conveyor face and aforwardly directed opening extending diagonally across and communicatingwith said conveyor face, an endless second band registering with saidforwardly directed opening and having a bottom edge closely confrontingsaid conveyor face to define therewith an extrusion opening and meansdriving said conveyor band and said second band whereby said second bandhas a component of movement in the direction of advance of said conveyorband.

11. An improved extrusion apparatus of the character describedcomprising an endless first band conveyor having an upwardly directedface along an advancing run thereof, a distributing chamber extendingtransversely along said conveyor upwardly directed face and havingformed therein a bottom opening confronting said conveyor face and aforwardly directed opening extending diagonally across and communicatingwith said conveyor face, an endless second band registering with saidfor- \vardly directed opening and having a bottom edge closelyconfronting said conveyor face to define therewith an 8 extrusionopening and means driving said conveyor band and said second bandwhereby said second band has a component of velocity in the direction ofadvance of said conveyor band and approximately equal to the speed ofadvance of said conveyor band.

References Cited in the file of this patent UNITED STATES PATENTS1,888,376 Duty Nov. 22, 1932 2,778,086 Wilcox Jan. 22, 1957 FOREIGNPATENTS 1,081,925 France June 16, 1954

